2nd Year Physics Chapter 19 Online MCQ Test for 12th Class Physics Chapter 19 (Dawn of Modern Physics)

The unit for Plank's constant is:

• Js^-1 A
• Jm B
• Js  C
• Jm² D

Joule second is the unit of.

• Energy A
• Wein's constant B
• Planck's constant C
• Boyle's law D

When platinum wire is heated, it changes to cherry red at temperature.

• 500^oC A
• 900^oC B
• 1100^oC C
• 1300^oC D

The physical quantity related to photon, that does not change in Compton scattering is.

• Energy A
• Speed B
• Frequency C
• Wavelength D

The converses of annihilation of matter is:

• Photoelectric effect A
• Relativistic effect B
• Pair production C
• Compton effect D

The minimum energy required for occurrence of pair production is:

• 1.022eV A
• 1.02keV B
• 1.02Me.V C
• 1.04MeV D

If the energy of photon is 10 eV and work function is 5 eV, then the a value of stopping potential will be

• 50 V A
• 2 V B
• 5 V C
• 15 V D

Who explained the photo electric effect.

• Max Plank A
• Einstein B
• Henry C
• Rutherford D

The unit of Plank's constant 'h' is.

• JC A
• J/C B
• JS C
• J/S D

Number of electros emitted in photo electric effect depend upon.

• Intensity of incident light A
• Frequency of incident light B
• Energy of incident light C
• Wavelength of incident of light D

The existence of positron was discovered in:

• 1929 A
• 1928 B
• 1931 C
• 1933 D

• Wien's constant A
• Planck's constant B
• Davison constant C
• Lumber's constant D

The numerical value of Compton wavelength is equal to

• 3.43 x 10^-12 m A
• 1.43 x 10^-12m B
• 2.43 x 10^-12m C
• 0.43 x 10^-12m D

The existence of positron in 1928 was predicted by

• Anderson A
• Dirac B
• Chadwick C
• Plank D

When the K.E. of photoelectric is zero, the frequency of incident photon is.

• Less than A
• greater than B
• Equal to C
• Much greater D

Wave nature of particle was given by:

• Clemensen A
• Louis de Broglie B
• Laster H. Germer C
• Clinton S. Davisson D

Application of wave like nature of particle is

• Photodiode A
• Optical microscope B
• Electron microscope C
• Compound microscope D